> UO economies themselves being matter of study
More than that, in regard to MMOs in general: both Cory Doctorow and Neil Stephenson wrote books involving exchange of money in MMOs, remarking that bringing a bag of gold to another dude in the game is an actual method of transferring money cross-border without oversight, used by mobs. I vaguely heard (and again mentioned by Doctorow) that the size of economy of larger games like WoW can dwarf not-so-small countries.